Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating activities:
Net income (loss)	$ 2,818	$ 23,498
Non-cash elements included in net income (loss):
Depreciation, depletion and amortization	56,908	56,968
Loss (gain) on investments	117	(439)
Gain on disposition of properties, plants, equipment, and mineral interests	(94)	(311)
Provision for reclamation and closure costs	2,247	2,005
Stock compensation	2,831	3,467
Deferred income taxes	(22,113)	10,652
Amortization of loan origination fees	967	926
Loss on derivative contracts	5,386	5,419
Foreign exchange loss	5,201	9,721
Other non-cash charges, net	2	17
Change in assets and liabilities, net of business acquired:
Accounts receivable	(1,150)	(15,910)
Inventories	1,594	(5,802)
Other current and non-current assets	3,896	268
Accounts payable and accrued liabilities	(10,937)	(3,820)
Accrued payroll and related benefits	(4,901)	3,135
Accrued taxes	4,408	(4,591)
Accrued reclamation and closure costs and other non-current liabilities	(1,359)	935
Cash provided by operating activities	45,821	86,138
Investing activities:
Additions to properties, plants, equipment and mineral interests	(45,964)	(76,960)
Proceeds from disposition of properties, plants and equipment	142	317
Purchases of investments	(23,280)	(16,088)
Maturities of investments	14,356	840
Changes in restricted cash and investment balances	1,102	(3,900)
Net cash used in investing activities	(53,644)	(95,791)
Financing activities:
Proceeds from sale of common stock, net of offering costs	9,610	8,121
Acquisition of treasury shares	(2,474)	(3,384)
Dividends paid to common shareholders	(1,981)	(1,914)
Dividends paid to preferred shareholders	(276)	(276)
Credit availability and debt issuance fees paid	(91)	(83)
Repayments of debt	(470)	(1,339)
Repayments of capital leases	(3,245)	(4,356)
Net provided by (cash used) in financing activities	1,073	(3,231)
Effect of exchange rates on cash	1,086	1,288
Net decrease in cash and cash equivalents	(5,664)	(11,596)
Cash and cash equivalents at beginning of period	169,777	155,209
Cash and cash equivalents at end of period	164,113	143,613
Significant non-cash investing and financing activities:
Addition of capital lease obligations	4,645	1,631
Payment of accrued compensation in stock	$ 4,240	$ 5,511